Let's go back to that triangle; seen from above there's three equal nodes.

我们回到那个三角形：从上往下，你看能到三个平等的节点。

youdao

These B nodes are equal, but they are not the same node.

这两个 B 节点是等同的，但它们不是相同的节点。

youdao

For example, if you create two empty element nodes named "foo" without any attributes, they are equal, even though they are not identical.

例如，如果创建了两个没有任何属性的、名为“foo”的空元素节点，那么它们是相等的，但是它们不是相同的。

youdao

Yup, so one total node, 2 minus 1 is 1, and that means since l is equal to 1, we have one angular nodes, and that leaves us with how many radial nodes?

一个节点，２减去１等于１,因为ｌ等于１,我们有一个角向节点，那剩下径向节点有多少个呢？

麻省理工公开课 - 化学原理课程节选

And when we talk about angular nodes, the number of angular nodes we have in an orbital is going to be equal to l.

当我们谈到角向节点时，一个轨道的,角向节点数等于ｌ

麻省理工公开课 - 化学原理课程节选

l l So what you can do for a 1 s is just take 1 minus 1 and then l is equal to 0, so you have zero radial nodes.

它等于1减去,是等于0的，所以没有节点，这和我们看到的是相符的。

麻省理工公开课 - 化学原理课程节选